Thread by @dana1981

The @WSJopinion page loves to publish junk from Bjorn Lomborg downplaying the risks posed by the climate crisis. Today he argues that potentially catastrophic 3.5°C global warming is 'economically optimal' based on Nordhaus' research. A thread 🧵 discussing the many errors here:

https://twitter.com/WSJopinion/status/1458827504366534657

1) It's based on one paper (a.k.a. "single study syndrome", a.k.a. "cherrypicking"). Lomborg tries to bolster his case by noting the paper is by Nordhaus who won a Nobel Prize. But Nordhaus has said high-warming scenarios are uncertain and dangerous.
theguardian.com/environment/cl…

2) The referenced paper was published in 2016, meaning it's 5 years out of date. The field of climate-economics has advanced dramatically during that time, yet Lomborg totally ignores the past 5 years of research. That's called cherrypicking.

3) Nordhaus' 2016 paper uses a discount rate of 4.25%, which is ridiculously high. Climate economists are now in agreement that for an intergenerational problem like climate change, the discount rate should be less than half that, maybe even close to zero.
eprints.whiterose.ac.uk/125845/1/Actua…

4) That's because higher discount rates effectively discount the welfare of future generations. They suggest that instead of spending money on solutions now, we should save money so we're wealthier in the future, which assumes continued economic growth (which climate might slow!)

5) Many experts have also argued that modeling an 'economically optimal' pathway is impossible in any case, because we can't predict future clean technology cost curves (wind & solar are so much cheaper than experts expected!). See @jgkoomey for example:
theguardian.com/environment/cl…

6) And in Nordhaus' 2016 paper, he also acknowledged, "When taking uncertainties into account, the strength of policy (as measured by the social cost of carbon or the optimal carbon tax) would increase, not decrease."
cowles.yale.edu/sites/default/…

7) But if we want to use the optimal pathway approach, Nordhaus' model has been updated. In a 2020 paper that incorporated the latest climate science & economics research. It found an optimal pathway of < 2°C, consistent with the Paris targets.
nature.com/articles/s4155…

8) Why is Lomborg referencing a 2016 paper rather than a 2020 paper that updated its results? Maybe because he's biased towards downplaying the urgency of the climate crisis and is cherrypicking research that affirms his worldview? Surely he doesn't suffer from confirmation bias!

9) Anyway, there's a vast body of literature finding that aggressive climate solutions are best for the economy, and also the welfare of society. Lomborg is a serial cherrypicker who ignores the vast body of research contradicting his argument. The End.
citizensclimatelobby.org/faster-transit…